Electrical potential difference and charge separation

  • Thread starter NeuralDynamics
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  • #1
NeuralDynamics
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Hello,

I am having a hard time trying to build these concepts in my mind. To generate a electrical potential difference I need to separate charges, right? But if I think in a capacitor, the electrical potential (e.g., battery) will charge the capacitor which, in turn, will keep the charges separated. So my question is what comes first: electrical potential difference or charge separation?
 
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  • #2
My understanding:
NeuralDynamics said:
To generate a electrical potential difference I need to separate charges, right?
Not necessarily. A changing magnetic field can generate a voltage (difference in electric potential) and we can generate a changing magnetic field without having to separate charges.
NeuralDynamics said:
So my question is what comes first: electrical potential difference or charge separation?


In general, neither comes first. Separated charges will generate a voltage and a voltage can cause a separation of charges. You can, of course, look at a specific system, say an uncharged capacitor, and find that a voltage was applied first and then the charges separated, but that's a choice.
 
  • #3
NeuralDynamics said:
To generate a electrical potential difference I need to separate charges, right? But if I think in a capacitor, the electrical potential (e.g., battery) will charge the capacitor which, in turn, will keep the charges separated. So my question is what comes first: electrical potential difference or charge separation?
The way that I prefer to think about it (in terms of cause-and-effect) is that an EMF (electomotive force) of some kind drives a current which creates a separation of charge and the resulting electric field (in your capacitor, for example). The changing magnetic field piercing a coil of wire mentioned by @Drakkith generates such an EMF. So does the battery in your example.
 

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